Tunnel silit



April 8 1924.

H. R. STRAIGHT TUNNEL KILN Filed. July 6, 1920 6 Sheets-Sheet l April 8 1924. 1,489,554

H. R. STRAIGHT TUNNEL KILN Filed July 6. 1920 e sheets-sheet 2 nlll Tiuemfqr.

H. STRAI GHT T UNNEL KILN Filed July 6. '1920 6 Sheets-Sheet 3 A ril 8 1924. 1,489,554

H. R. STRAIGHT TUNNEL KILN Filed-July- 6 r1920 6 cs-Sheet 4 o O, o; O

April 8 1924.

H. R. STRAIGHT TUNNEL KILN 6 Sheets-Sheet 6 Filed July 6 1920 00 In 0. on O. l. .0

Patented Apr. 8, i924.

treat o HALVER R. STRAIGHT, OF ABEL, IOWA.

TUNNEL ZELN.

Application filed July 8, 1320.

To all whom it may concern.

lie it known that I, Hnnvne R. S'rimieiir, a citizen 01" the United States, residing at Adel, county of Dallas, State oi lowa, have invented an Improved Tunnel Kiln, of which the following is the specification.

This invention relates to what is known as tunnel or continuous kilns for burning hollow building blocks or drain tile.

There have been quite a number of these kilns constructed, and operated for burning china ware and such small articles, but so far as I am aware no kilns of this type have been successfully constructed for rapidly and eiliciently burning brick or hollow building blocks and drain tile.

There is a very large amount of material used in articles of this kind and requires a very large number of heat units to burn them, which must be very rapidly and uni lornily imparted to the ware without cracking or warping it. Even more care must be tak n in the cooling of the ware, which also to be etticient in operation must be very rapidly done.

In ware of this kind the temperature may be very rapidly increased, or decreased without injury to said ware it the temperature is evenly and uniformly increased or decreased.

The object of my invention is to provide a tunnel or continuous kiln for burning hollow building blocks or d'ain tile, etc., of simple, durable, and comparatively inexpensive construction, and to provide in such a structure, improved means for controlling the drafts for pro-heating, burning, and cooling, so that the ware may be moved through the kiln in a comparatively short time without cracking or warping it.

A further ob ect is to pro iee new and improved means; whereby expansion and contraction may take place due to the heat from the furnaces, without destroying the main wall construction of the arch or tunnel portion of the kiln.

it further object is to provide in a tunnel kiln having a train of cars operated interinittingly, improved method of entry, and exit for the cars to said kiln.

it still further object is to provide in a tunnel kiln having a train of ware bearing cars, improved floor for said cars whereby the cooling and heating may be more elliciently carried on within the kiln.

Serial No. 394,344.

A further object is to provide in a continuous kiln means whereby a series of cars may be advanced freely through said kiln, and be subjected to a series of controllable tempt ares, or zones, each of which may be note or lass independently regulated, wahout transverse partitions separating said zones, within the kiln.

".ihcse and other objects will be apparent to those skilled in the art which need not be mentioned in detail.

ficlerring to the accompanying drawings,

i is a plan view of my improved kiln, and

Fig. 3 is a side elevation of the same.

Fig. 23 is a transverse section view taken on the nc 25---;3 of Fig. 1.

Figure a is a transverse sectional view taken on the line l'-l of Figure 1.

5 a transverse sectional view taken on the line 55 of Fig. 1, through the burning zone of the kiln.

b is a detail longitudinal sectional vie taken on the line 6-6 of Fig. 1, of the cooling end of the kiln.

Fig. '2' is a detail longitudinal sectional view taken on the line i -7 Fig. 1 of the burning zone and a portion of the pro-heating zones.

8 is a detail elevation of a portion of the interior or" the cooling zone, showing the draft openings.

F i) is a detail elevation of a portion of the interior or the burning zone, showing the heat conducting openings.

Fig. 10 is a detail sectional plan view taken on the line 10-1O of Fig. 5.

n it is a detail sectional view taken on the line 11-11 of ig. 1 showing the mechanism for forcing toe draft to the burners.

l ig. 13 is a detail sectional view taken on the line of Fig. 5 showing the draft I devices.

iig. ll is a t etail. sectional view showing one of the tov'. for imparting a positive motion to the air currents.

f improved kiln comprises substantially l part l0, and "furnace portion 11. tunnel is formed 01 parallel and vertical walls 12. Each wall rests on a base portion 13, the inner wall of which projects inside of the inner face or" the wall 12 a Considerable distance. The upper edges of the walls 12 are designed to receive an arch portion l l between them. The said walls 12 are held against lateral or outward movement by means of the vertical beams 15 and tie rods 16.

This arch portion 14 is constructed some what differently at various positions of the tunnel, as will be more fully set forth, as each section is described in detail.

Each of the inner faces or the base portions 13 are provided with a trough 17 designed to be filled with a granulated tire proof material, such as the clay or sand.

The bottom of the tunnel is provided with. tracks 18, designed to receive a train or cars 19, each oli which are provided with, floors 20, formed of a refractory material, such as fire brick.

The floors 20 are of such a width that their ends will terminate at a point substantially above the center or the troughs 13'. and are designed to have downward projectingplates 21, designed to enter the said troughs 17, these plates are for the purpose of forming a seal, so that the lower and metallic parts of cars may be protected from the intense heat of the burners.

The floor 20 of each of the cars 19 is provided with a series of conductor members 22, formed of a refractory material. Each of said members being placed on said floor, adjacent to and transversely of each other, and provided with a longitudinal opening 23. Each member 2:2 has in its upper :tace a number of openings 2%, in communication with the opening at for the purpose GTE conducting currents of air, as will be more fully set forth. 7

To permit cars to enter and be removed without allowing an excessive amount cold air entering the kiln every time a c:

is moved into or out of the kiln. ha s provided what I shall term i cut and exit vestlbul the entry vest Jule ht ng; located doors 25 and 26, when in an opened position.

Sectional views of the cooling end of the lriln are shown in Figs. 3. and h. ln Fins. 5:3 and 4t it will be noted that the walls r comparatively thin. and the arch l l formed directly in said walls, near th upper ends. The space ahove the arch l0 tilled with heat insulating material. Eacn of the base portions 18 are provided with a conduit 80, and on their upper face a series of arches of fire rool material, to form passage ways 31, in communication with the conduits 30, and of such a height as to be in line with the openings of the floor members length of a single car.

Each of the passage ways are provided with a valve 32, formed or lire proof mat r a d designed to be operated by means d extending to the ex". rior oi the tne extreme end of the cooling end of iln l have provided a sheet metal per-- S i, and a top 35, the th sides 3 r "s on the top 1d The si s 0 are spaced apart such a distance that a crmsilerable space will be prmrided between them and the ware oi the cintaincd cars this is to permit any blocks that might fall oil of the car to lodge on top of t ie arches without loching car, or scraping ic rewaining blocks oil. The sa fl pert-ulster is or such a size that a considerable space 36, is left between it and the walls 152.. and arch 14-. Tl'iis space is for the purpose of receiving cold air direct from the outside through air intake pipe 37. The space 36 is pro vided with a. series of hafiie plates 38, for the purpose of causing the air to circulate adjacent to the side members i'l lto become warmed by radiation. Tl

inc top 35 is pro vided with a series of openings 35. the number and size of which are to be de termined by experin'lent.

The warmer end of formed of fir proor material, while the cooler end is formed of sheet me al, the fireproof portion being pr l resist the high temperatures, while the sheet metal portion is provided to permit the better radiation and conduction of the heat.

Fig. 5 is a sectional view through the ill"- ing or burning You it will be noted that the walls 12 are somewhat 'i'Jhicl-Zer at this section than at the cooling end of the tunnel.

3r series of arches are provided on the base wall .13. similar to those "for the dueling end. except the space or": each is substantially equal to width or one of the hioclrs t car floor. ".vill he seen ll'OlTl b at the passages under the .5: .1 Y .r arches 39 oL one side oi the hiln are deon the cars, as nate block 22 will radiate heat to the cool er ends of the intermediate lDlOthS.

A furnace 11 is built separate and adja Ice ill

' in Fig. 11.

cent to each of the walls 12 and opposite the burning zone, and comprising wall members 40, and an arch 41, one end being closed, and the opposite provided with an automatic stoker device 42, Fig. 11. This stoker may be of any suitable construction and forms no particular part of my present invention. I have however provided a fan device 43 having an outlet pipe 44 leading directly to the the box of the stole-r, the fan 3 is driven directly by a variable speed motor, 46, Figs. 1 and The intake of the fan is in communication with the forward end of the air passage as shown The outer walls are supported by vertical beams 47 and tie rods L8. Each of the inner walls tO is provided with a passage way 49 opposite and in line with the passage way under the arches 39, each of the passageways a9 is provided with a tube 50 formed of a refractory material, these tubes 50 are somewhat smaller than the passages 49 and are designed for a fireproot lining and to bridge the slight space between the walls 12 and l0. These tubes may be removed and replaced by new ones when burned out. They also permit a slight movement of one wall relative to the other due to expansion or contraction, etc., without injury to the main tunnel walls. A new furnace may also be substituted for the old one when burned out, without having to rebuild the tunnel walls. A slidable brick or block 5i is mounted adjacent to the furnace end of each of the tubes 50. Above each block 51, in the arch ll I ha e provided a vertical pipe 52 having a detachable cap 53, by removing said cap a poker may be inserted in the pipe 52, and the block 51 moved to position over the end of the tube 50, to form a damper for regulating the flow of air through said tubes. y removing the cap 53 the condition of the fire may also be determined.

Adjacent to each side of the cooling zone slightly above the passage 31, I have provided a cold air pipe 54. In communication with the pipes 5-1, I have provided a series of lateral pipes 55 communicating with the space 36. A butterfly valve is provided for each ot the pipes 05 and is operated by means a handle 57. Each of the arches of the passages 31 are provided with an opening 58, a valve 55) is provided for said openings and has a rod 60, by which the valve may be moved to an opened or closed position, as shown in Figs. 3 and t.

lih'uin'ted above the arches 14 I have provided a passage way 61 substantially the full lcngh or" the kiln, the arch 14 is provided with a series of openings 62, having a covering brick or block 63 above each of said openings. In the cover of the passage (31 l have provided a pipe 6 having a detaclmhle cap 65, by removing the cap 65 and inserting a poker or iron rod through the pipe (34, the block 63 may be moved to one side so that the condition of material beneath may be observed. By closing the cap (35 and leaving the opening (52 partly uncovered, a portion of heated air within the kiln may be drawn oft, as will again be referred to.

The firing zone is provided with a tireproo't lining 3G, and an inclined arch 67 Figs. 5 and 7. These walls are so constructed that they may be easily removed nithout destroying the construction of the main tunnel oi the kiln.

The pro-heating zone, Fig. 7 is constructed similar to the cooling Zone, having the same arch construction over the base portion 13, with the exception of the hous- .ing 34;, which is omitted.

'ihe intake end of the pro-heating zone, or section, is provided with a vestibule similar to the, one on the cooling end of the kiln.

For forcing air into the kiln I preferably use a low pressure blower, something like the one shown in cross section of Fig. 13, one of which is connected to the pipe 37. Each of the pipes 54. also have one end in communication with the pipe 37 as shown in Fig. 1.

The passage 30 has a partition 70, so that the said passage is divided into two parts, the one at the cooling end of the kiln being in communication with the fan 43, the other one in communication with the pipe 71, which is in turn connected to the intake side of the blower 68, the cooling ends of the passages are also connected to an under ground conduit 72, which is designed to lead to a drier room.

The passage way 61 is also connected with the conduit 72 by a pipe 73.

In practical operation, the cars 19 are filled with hollow building blocks, or d ain tile stacked on end, so that vertical air pas sages are formed, and are in communication with the openings 24, in the members 22. The cars are then moved to the outer door 25 of the preheating end of the kiln, the door is then opened and the car moved into the kiln. This is repeated until the preheated end of the kiln is filled with cars, the doors 25 and 9.6 at the opposite end of the kiln are then closer., and fires started in the furnaces, the blowers 6S and 68 are then started, the blower 68 would then cause cold air to be forced into the pipe 37, and in turn to the space 36, above the percolator St. The alves 32 at the outer or cooler end of the kiln should be closed, thereby causing the air to be forced to the forward end of the cooling zone, the forward valves however being left open so that air could be drawn through the fan casing at?) and to the furnaces 11. The heated air is then drawn from sai furnaces through the passages 49 and the tubes to the interior of the burning chamber, thence upward and down through the ware, to be pro-heated through the opening 24- of the passage 23, and to the 31 under the arches, shown i 8, then downward through the passages to the pipe 71 and out through the suction blower (58. The pro-heating of the material may be graduated by inai'iipnlating the valves 32, so that each car may get the proper amount of heat. After the cars within the pro-heated zone have been raised to the proper tsniperature new cars may be added one at a time; this will cause (hem to enter the burning zone where tl y are to he stopped so that one of the floor members is opposite one of the tubes 50, the hot gases will enter the opening 23 as shown arrows in 10, then upward through i hollow bloclt and tile then forward to t pie-heating zone and downward and 01 ward as before described.

The cars will then be intermittently moved rearward until the cooling zone is filled, the opening 23 will then be opposite the pa. sages 81, the valves 32 should then be opened and the air allowed to enter the passage 30, the operation will then be as follows,-the cold air will enter the space 36 above the metallic portion of the percolator, a certain proportion of which will flow through the openings in said housing to the vertical passageways in the stacked ware, d wnward through. the openings 24 and 23, and to the passages 30 and 31; by the proper distribution of the openings 35, the air may be very uniformly distributed or percolated to the ware beneath, if it is found that the ire on the outer sides of the ware is cooling too fast, some of the outer openings 35 may be closed, or vice-versa, or if it is found that the material on a car at a certain position of its movement is cooling too fast, then some of the openings above said car may be closed up, or if it is cooling too slowly. some of the openings may be opened up. Regulation may also be somewhat accomplished by opening or closing the valves The battle plates 38 are placed so that the air which does not enter the openings 35 may be pulled down past the sides 01 and heated therefore by radiation this air will also take on heat from the arch portion of the percolator, some of the air will again pass through the next series of openings 35', but will have become slightly heated, thus as the unused portionof air advances forward. past each of the baffle plates 38, it will become warmer and warmer, the idea being to deliver the air to the ware at a temperature just a few degrees below the temperature of the ware, so the said ware willnot become chilled and cracked from unequal contraction. If it is found that the llQlllPQltlilUl'iB of the advancing air above housing raising in tcinperatiuc too 11. part of the heated an may be taken oil through the conduit 61 and the opening 22, this wbnld have a tendency to reduce the volume of air iassing through the ware at the hot Zone. Cold air may be admitted rough the tube 535, or if it desired to l.=;lS? the temperature of the said section instead of lowering it the valve 5-?) would be opened and the valve 56 closed, in an adjoining rear section then some of the cooler air would be d fawn oil" through the passages 31 and leaving air in the said section to more slower, and cool slower, thus it will be seen that by the proper operation of the valves 32--59-b6 and 63, the cooling of the ware may be very rapidly accurately, and finely graduated, so as to prevent cracking and warping. and the ware given the proper degree of herdnes. The material on the various parts of the cars w'll be uniforn' v treated. One advantage of this con- Stl'lK ion is that a considerable space may be leitbetween the sides of the pile of ma terial on the cars and the walls of the housings or interior iinings and yet have a series of substantially distinct zones, each of which may be more or less independently controlled without having a transverse partition for each zone, by permitting considerable spa e between the ware and wall, a block aecidently falling off the pile would not lodge and stop the cars, as it. would simply lay on the top of the air conducting arches.

It will also be notec that no air will enter the kiln, for supplying the furnaces or otherwise, except through the pipe 37 and this is fed at uniform volume and pressure by the blower 68. By the special arrangement of the propelling members of the blowers of this sype, the flow of air through the pipe 37 would not be affected by outside atmospheric conditions or the direction of a whirling and variable wind. In a similar manner the suction blower titl will operate to uniformly and continuously draw the gases of the cooling chamber in such a manner that the currents of air will discharge froin the kiln and deliver them to the outside atmosphere withoutbeing influenced by the action of the wind. The blower 68 should be so operated that a slight pressure is applied to the cooling end, while the door 68 should be of such dimensions and so operated that a slight vacuum is created at the discharge end of the kiln.

Both of said blowers act somewhat as meters, one feeding a predetermined volume of gas to the kiln, while the suction blower draws a predetermined and greater volume of gas from the ltiln. The ditlerence of volume entered by the two blowers being due to the difference in temperatures of the gases as they enter and leave the kiln.

I am well aware that nnvans have been provided for opening and closing the air passages leading to and from the kilns of this type, but none of them have "ed mechanical means whereby a predetermined volume of gas may be fed to the ltiln and a predetermined volume taken from, without the influence of outside atmospheric conditions.

The stability of the air within the kiln is maintained when the cars are taken in and out, by means of the vestibules at each end, provided with the doors and 2G. lVhen -it is desired to remove a car from the ltiln,

the door 26 is opened and the cold car moved to the vestibule, then said door 26 is closed, and the door 25 opened, the car s then moved to the exterior of the kiln. The cars are moved into the kiln at the opposite end by a reverse operation; by this arrangement the kiln may be made practically air tight except through the conducting passages which are under absolute control of the pressure and exhaust blower.

A conductor 72 is provided. and in coinmunication with a drier not shown both of which are exhausted by a blower similar to 68*.

The conductor 72 communicates with the passage 30 at a point somewhat ahead of the fan 43, and removes a large part of air at a medium temperature, the remaining hot air is driven through the grates of the stokers by the said fans 43, the forward ends of the pipes 54 however are in communication with the intake of the Fan for supplying cold air, if the temperature of the air from the passage 30 is too high this cold air is controlled by a valve 75'. Somctimes it is desirable to hold the ware at a given temperature in the burning process to permit oxidation of the carbonaceous materials, I can accomplish this by means of the slides 5".

Thus it will be seen I have provided a tunnel kilncomparatively air tight, and unafliected by outside atmospheric conditions, and in which the temperature of the various Zones are under absolute control of the operator, and one in which the fuel economy is reduced to the highest degree o'r' ctliciency, also in which the repairs and upkeep are reduced to a minimum.

Having thus described my invention I claim:

1. In a device of the class described, a tunnel designed to receive a series of movable cars, and to be divided into preheating, burning and cooling zones, and an adjacent and independently constructed furnace at each side of said burning zone, the adjacent wall of each having a series of corresponding openings, each corresponding set of which is provided with a loosely mounted refractory tube for conducting heated gases from the furnace to the said burning zone.

2. In a device ot the class described, a tunnel designed to receive a series of movable cars, and to be divided into preheating, burning and cooling zones. and an adjacent and independently constructed furnace at each side of said burning zone. the adjacent wall of each having a series of corresponding openings, each corresponding set of which is provided with a loosely mounted refractory tube for conducting heated gases from the furnace to the said burning zone, a. car receiving vestibule at each end of said tunnel for the purpose stated.

3. In a device of the class described, a

tunnel designed to receive a series of movable cars, and to be divided into preheating, burning and cooling zones, and an adjacent and independently constructed furnace at each side of said burning zone, the adjacent wall of each having a series of corresponding openings, each corresponding set of which is provided with a loosely mounted refractory tube for conducting heated gases from the furnace to the saidburning zone, and a damper for each of said openings.

4;, In a device of the class described, a tunnel designed to receive a series of movable cars, and to be divided into preheating, burning and cooling zones, a furnace adjacent to one side oi said burning zone having a series of openings communicating therewith, to conduct heated gases from the said furnace to the said burning chamber or zone, and a damper tor each of said openings.

5. In a device of the class described, a tunnel desimied to receive a series of movable cars. and to be divided into preheating, burning and cooling zones, a car receiving vestibule at each end of said tunnel, said vestibule being provided with a. door at each end designed to be alternately opened and closed so'that a car may be moved into or out of the tunnel without unsealing the ends, mechanical means for feeding air under slight pressure to the cooling end of said tunnel, mechanical means for producing a slight vacuum at the preheating end, both of said means being capable of producing a constant flow of air under a constant pressure and at a uniform velocity, and an adjacent and independently constructed furnace at each side of said burning zone, the adjacent wall of each having a series of corresponding openings, each corres onding set of which is provided with a loose y mounted burning and cooling zones, :1" ing vestibule at each end of so, i i, vestibule being provided with a door 2 end designed to be alternately o on closed so that car may be 1 out of the tunnel Without uus mechanical means for a slight pressure to the cooli g tunnel, mechanical means it slight vacuum at the preheati one of said means being capable of producing a constant flow of air under a constant res sure and at a uniform velocitv, and ad jacent and independently constructed. furnace at each side of said burn ng zone, the adjacent Wall of each ha l ries of corresponding openings, each corresponding set of Which is provided with loosely mounted refractory tube for con acting heated gases from the iurnz-ice to the said burning zone, and a damper each of said openings.

7. In a device of the class described, tunnel designed to receive a series of movahl cars, and to be divided into 1'ire-heating, burning and cooling zones, a war receiving vestibule at each end of tunnel, mechan ical fill-21,118 for feeding air under sli ht pressure to the cooling end of said tunnel, and

mechanical means for simultaneous y produclng a slight vacuiun at the pro-heating end, both of said means being capable of producing a constant flow of air under a constant pressure and at a uniform velocity.

8. In a device of the class described, a tunnel designed to receive a series of movaacuum at the under side of said percolator housing.

9. In a device of the class cescribed, atunuel dcsig ed to receive a series of movable I and to be di ided into preheating, in ing and cooling zone a car receiving vestibule at each end of said tunnel, said cooling zone being provided with a i: rcolator llOl'if-Elllg over sai d cti mechanical cans for feeding air under slight pressure to the outside of said percolator housing, mechanical means for producing a slight vacuum at the under side of said percolator housing,'and means for regulating the flow of air at the various points Within the said housing.

' 10. In a device of the class described, a

tunnel designed to receive a series of movable ll? divided into preheating, burnzones, :1 ca r ecoiving vestiziel, said cooling tcolator housslight pressure to the out percolator housing, mechanical or producing a slight vacuum at the iidc of said ircolator hour ig, and went and independent v constructed at each side of said iii hing zone, the va -l of each ha i series of coropen each c rrespond ng set ich provided with a loosely mounted :tory tube for conducting heated gases om the furnace to the said burning zone,

11. In a device of the class described, a tunnel designed to receive a series of movable and to be divided into preheating, burnand cooling zones, a car receiving vestido at each end of said tunnel, said cooling zone being provided With a percolator housing over said cars, mechanical means for feeding air under slight pressure to the outidc of said percolator housing, mechanical neaus for producing a slight vacuum at the uider side of said percolator housing, means ror regulating the flow of air at the various points Within the said. housing, and an adjacent and independently constructed furnace at each side of said burning zone, the adjacent Wall of each having a series of coro ienings, each corresponding set 1 is provided with a loosely mounted "victory tube for conducting heated gases om the furnace to'the said burning zone.

12. In a device of the class described, a tunnel designed to receive a series of movable cars, and to be divided into preheating, burning and cooling zones, said cooling zone being provided With a percolator housing over said. cars, mechanical means for feeding inider slight pressure to the outside of o percolator housing, and mechanical A C for producing a slight vacuum at the under side of said percolator housing.

13. In a device of the class described, a tu nel designed to receive a series of movable s, and to be divided into preheating, burning and cooling zones, said cooling zone being provided With a percolator housing over said cars, mechanical means for feeding air under slight pressure to the outside of said percolator housing, and mechanical means o producing a slight vacuum at the under ride of said percolator housing, means for producing a series of successive high temperature zones outside of said housing.

ll. The combination of a tunnel kiln having a series of transversely arranged inlet and outlet air passages, and a series of kiln cars each of which is provided with a floor comprising a series of fire proof, adjacent, and transversely arranged conductor memhers, each of which has in its upper side a nnin'iicr of openings in communication with the conductors of said members, said series of passages being in a horizontal line with the said conductors, independent means for "rolling the flow of through each of passages, mechanical means for feeding air under a slight pressure to a number of said passages and mechanical means, for producing a slight vacuum in the remainder of said passages, both of said means oeing eapaljiie of producing constant flow of air under a constant pressure, and at a uniform velocity.

15. In a device of the class described, a tunnel designed to receive a series of movable cars and to be divided into preheating, burning and cooling zones, and an adjacent and independently constructed furnace at one side of said burning zone, the adjacent walls of said furnace and said kiln having corresponding openings to permit the products of combustion from said furnace to enter said kiln, said furnace being so con structed that it will expand and contract 25 independently of said tunnel.

HALVER R. STRAIGHT. 

